A widely used electrical connector employs a receptacle contact into which is fitted a tab contact. One or both of the contacts may be crimped onto electrical wires or fitted onto devices such as switches, lamps, and the like supplied with current through such contacts. Typically, a plastic housing is employed with respect to one or the other of the contacts and some means is provided to lock the contact to the housing. Connectors of this type are disclosed in Japanese Patent 51-30270 and are represented in the views of the prior art shown in FIGS. 8 and 9 of this Application. There, the connectors include a housing 1 which includes internally a lance 10 having engaging surfaces 12 and 13 in the contact passage 9 formed by top wall 2, bottom wall 3, and two side walls 4. The contact 15 is inserted and held within the passage 9 of the housing, and has a contacting portion 18 with a floor part 19, side part 20, bent in a semi-circular form from each side thereof. A crimping barrel 16 joins the contact to a conductor 17 carried in an insulating jacket to form a wire. A latching tang 21 is shown in FIG. 8 to extend inwardly of the side parts 20 and latch to the terminal tab (not shown) connected by contact 15 in a well-known manner. The rear edge 22 of the contact as shown in FIGS. 8 and 9 includes surfaces which provide locking engagement by a lance 10 of the housing 1. As can be seen in FIG. 9, the contact 15 is inserted into the housing 1 with the lance 10 and the surfaces 12 and 13 thereof engaging the rear edge 22 of the contact to lock it within the housing. Also shown in these figures are the beveled front surfaces 6 and 7 which act to guide the insertion of a tab terminal through opening 8 within the contact 15.
Connectors as described are widely used in automotive and appliance applications wherein fairly large tensile forces may be expected, applied through the conductor 17 to the terminal tending to pull the connector apart, the receptacle part 15 away from the tab part causing a failure of connection. This is particularly true when the housing 1 is latched or locked in some fashion to put a strain on the latch 10. In vehicles, for example, road shocks and vibrational displacements can cause a failure of the latch and thus a failure of the connector.
The solution to the foregoing has been to provide some sort of double locking feature wherein, in addition to lance 10, a plastic element or other element is inserted through the housing in a manner to engage the terminal and prevent its displacement, acting in addition to the lance 10 to provide a so-called double locking feature. Typically, these approaches have resulted in a connector of an overall greater size than those not having the secondary, or double lock, feature.
Accordingly, it is an object of the present invention to provide an electrical connector having a double lock feature which is smaller than heretofore available. It is a further object to provide a connector having a double lock feature which is usable with existing connector contacts and with slight modifications to existing housings. It is still a further object of the invention to provide a receptacle and tab connector utilizing standard contacts and housings with the addition of a double lock part fitted completely within the housing.